Shaftless cooling fans

ABSTRACT

A shaftless cooling fan is comprised of a fan body pivotally mounted on a fan base through a configured shaft. The fan base further comprises a plurality of vents, an electrical device for driving the fan body, a recess in its top and bottom ends for positioning a shaft end respectively, and a plurality of electromagnets surrounding the recess in the bottom end. The fan body is rotatably positioned in the fan base by placing the shaft ends in respective recesses, and there is also a plurality of permanent magnets aligned surrounding the lower shaft end, in which every permanent magnet is comprised of a magnetic N-zone, an S-zone, and a Neutral zone, and repeatedly structured. Every electromagnet is controlled by the electrical device to form magnetic zones corresponding to the N-zone, S-zone, and Neutral zone of each the permanent magnet, such that each permanent magnet is driven to rotate the fan body by changing the magnetic zones in each electromagnet.

FIELD OF THE INVENTION

This invention relates generally to cooling fans, more specifically, itrelates to a shaftless cooling fan, in which an electromagnet is appliedto interact with a permanent magnet in a fan body so as to rotate thefan body without needing any conductive contact or a shaft, thus toreduce the frictional resistance of the cooling fan.

BACKGROUND OF THE INVENTION

As the higher the operating speed of a computer is raised, the more theheat is generated in that computer, therefore, a delicate design of heatdissipation of computer is considered a very important factor toengineers.

For cooling the environment of computer in order to operate normally,one or more cooling fans are usually arranged in a computer formaintaining inside temperature under workable conditions. The coolingfan is generally comprised of a fan body pivotally jointed to a fan basethrough a shaft, where the shaft is rotatably fixed in the fan base bymeans of bearings or some other lubricating devices and electricallyconnected with an electrical device for driving the fan body.

In the foregoing fan structure, since the electrical connection fordriving the fan body to rotate is made through the shaft, therefore theconventional jointing manner of the shaft with the fan base cannot bewaived, and accordingly, nor can the frictional resistance be thoroughlyeliminated. Moreover, just as the frictional resistance to a genericmicro-mechanism, the heat generated from the frictional resistance is ofequal importance to a notebook computer, which requires a highefficiency of heat dissipation. And a final point to be emphasized isthe assembling accuracy of the conventional fan structure. An assemblingof low precision could result in an unsmooth rotation, vibration, oreven impairment to the fan structure.

SUMMARY OF THE INVENTION

The primary objective of this invention is to provide a shaftlesscooling fan for the purpose of improving the conventional fan structure.

In order to realize abovesaid objective, the shaftless cooling fan ofthis invention is comprised of a fan body pivotally mounted on a fanbase through a configured shaft. The fan base has a plurality of vents,an electrical device for driving the fan body, a recess in its top andbottom ends for positioning a shaft end respectively, and a plurality ofelectromagnets surrounding the recess in the bottom end. The fan body isrotatably positioned in the fan base by placing the shaft ends inrespective recesses, and there is also a plurality of permanent magnetsaligned surrounding the lower shaft end. Every permanent magnet iscomprised of a magnetic N-zone, an S-zone, and a Neutral zone, andrepeated to form an annular structure. Every electromagnet is controlledby the electrical device to form magnetic zones corresponding to theN-zone, S-zone, and Neutral zone of each the permanent magnet. Byarrangement in this way, each permanent magnet is driven to rotate thefan body by changing the magnetic zones in each electromagnet.

The merits of the shaftless cooling fan of this invention might besummarized as follows:

-   -   1. Since the shaft ends are rotatably point-contacted with the        recesses without electrical connection, therefore the frictional        resistance of shaft can be significantly reduced;    -   2. As the frictional resistance is reduced as described, the        driving power required and heat generated can be accordingly        lowered;    -   3. The rotation speed of the cooling fan can be raised        accordingly because of the reduced frictional resistance;    -   4. The rotatable jointing of the shaft to the recess, requires        no high-precise assembling so that cost saving is possible; and    -   5. The rotatable jointing of the shaft to the recess in the        manner of point-contact may simplify the assembling process.

For more detailed information regarding advantages or features of thisinvention, at least an example of preferred embodiment will be fullydescribed below with reference to the annexed drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The related drawings in connection with the detailed description of thisinvention to be made later are described briefly as follows, in which:

FIG. 1 is a three dimensional view showing the structure of a shaftlesscooling fan of this invention;

FIG. 2 is a cutaway sectional view of the shaftless cooling fan of thisinvention;

FIG. 3 shows a schematic distribution diagram of magnetic poles of apermanent magnet and electromagnet in the shaftless cooling fan of thisinvention;

FIG. 4A is a schematic distribution diagram of magnetic poles showingthe interactive force between the permanent magnet and the electromagnetin the shaftless cooling fan of this invention;

FIG. 4B is a schematic view showing thee force exerted upon a magneticN-zone of the permanent magnet in the shaftless cooling fan of thisinvention;

FIG. 4C is a schematic view showing the force exerted upon a magneticS-zone of the permanent magnet in the shaftless cooling fan of thisinvention;

FIG. 5A is a schematic view showing an initial state of the shaftlesscooling fan of this invention;

FIG. 5B is a schematic view showing another initial state of theshaftless cooling fan of this invention; and

FIG. 5C is a schematic view showing yet another initial state of theshaftless cooling fan of this invention.

DETAILED DESCRIPTION OF THE INVENTION

A preferred embodiment of shaftless cooling fan of this invention ismainly comprised of a fan body (1) installed on a fan base (2) as shownin FIGS. 1 and 2.

The fan base (2) is substantially a square hollow casing having at leastan opening formed in its top end and side wall, respectively. A recess(21) for positioning a shaft end is formed at respective correspondingpositions of the lower surface of a top end and the upper surface of abottom end in the fan base (2). Also, an electrical device (not shown)for driving the fan body (1) is arranged in the fan base (2) andextended to the upper surface of the bottom end of the fan base (2) toform a plurality of electromagnets (22), which is aligned surroundingthe recess (21).

The fan body (1) is composed of a configured shaft (11) and a pluralityof fan leaves (12) outwardly extended therefrom, in which the top andthe bottom end of the configured shaft (11) are tapered into respectivesharp ends (13) for being accommodated in the recess (21) individuallyto have the configured shaft (11) rotatably located in the fan base (2).In addition, a plurality of permanent magnets (14) is disposedsurrounding the sharp ends (13) on the bottom face of the configuredshaft

The contact face of the sharp end (13) of the configured shaft (11) incontact with the respective recess (21) is deemed as a point-contact.

FIG. 3 shows a schematic distribution diagram of magnetic poles of apermanent magnet and electromagnet in the shaftless cooling fan of thisinvention.

As shown in FIG. 3, the magnetic poles of the permanent magnets (14) onthe bottom face of the configured shaft (11) are spaced equally andaligned annularly in a same circumferential direction to formintermittently inserted magnetic N-zones (14 a), S-zones (14 b), andNeutral zones (14 c). Further, the electromagnets (22) in the fan base(2) are controlled by an electrical device for defining a plurality ofannularly aligned magnetic zones (22 a), in which each magnetic zone (22a) is annularly and repeatedly controlled to create a magnetic N-zone,an S-zone, and a Neutral zone cyclically, and is controlled by a clockto produce a Neutral zone, an S-zone, then an N-zone sequentially androtationally. By the foregoing arrangement and the commutation of eachmagnetic zone (22 a) of the electromagnets (22), every permanent magnet(14) on the bottom end of the configured shaft (11) is either repulsedor attracted to hence drive the configured shaft (11), and accordinglythe fan body (1), to rotate.

Referring to FIGS. 4A, 4B, and 4C and observing all the permanentmagnets (14) and electromagnets (22) in an imaginary straight line, theperiodicaly and cyclically appeared N-zones (14 a), S-zones (14 b), andNeutral zones (14 c) of the permanent magnets (14) are assumedly zigzagaligned against that of the electromagnets (22) in an initial state.Therefore, every N-zone (14 a) of the permanent magnet (14) is repulsedtheoretically by the corresponding N-zones (22 a) of the electromagnets(22) such that a resultant force is consequently formed to drive theshaft (11) to rotate in a direction shown in FIG. 4B. Similarly, everyS-zone (14 b) of the permanent magnet (14) is repulsed theoretically bythe corresponding S-zones (22 a) of the electromagnets (22) such that aresultant force is consequently formed to drive the shaft (11) to rotatein a direction shown in FIG. 4C. Hence, the shaft (11) will rotate in adirection depending upon the total resultant force that exerts on thepermanent magnets (14).

Then, after a short time is elapsed, the order of the magnetic zones (22a) of each electromagnet (22) is changed rotationally by way of: theoriginal N-zone (22 a) into a Neutral zone (22 a), the original S-zone(22 a) into an N-zone (22 a), and the original Neutral zone (22 a) intoan S-zone (22 a), so that the shaft (21) will rotate in the samedirection. Therefore, under a proper means for controlling the magneticzones of each electromagnet (22) in the order of a Neutral zone, anS-zone, then an N-zone, the shaft (11) could be kept in continuousrotation.

As indicated in FIGS. 5A, 5B, and 5C, an initializing process isindispensable at the first place for starting a shaftless cooling fan ofthis invention for controlling the alignment of the magnetic zones (22a) of each electromagnet (22) in the order of a Neutral zone, then anS-zone, and followed by an N-zone, and holding that order for an optimumtime period. As a result, in the initial state, an attractive force anda repulsive force from an S-zone (22 a) of each electromagnet (22) areapplied on every N-zone (14 a) and S-zone (14 b) of each permanentmagnet (14), respectively, hence each N-zone (14 a) of every permanentmagnet (14) will be positioned right above an S-zone (22 a) of eachelectromagnet (22). Then, the initializing process is going to dispensean N-Zone and a Neutral zone to two immediate neighboring magnetic zones(22 a) of The S-zone (22 a) in each electromagnet (22), then change themagnetic zones sequentially in the order of a Neutral zone, an S-zone,then an N-zone, so that the configured shaft (11) is driven to rotatecontinuously in the state as above-mentioned.

In the above described, at least one preferred embodiment has beendescribed in detail with reference to the drawings annexed, and it isapparent that numerous changes or modifications may be made withoutdeparting from the true spirit and scope thereof, as set forth in theclaims below.

1. A shaftless cooling fan, comprised of a fan body having a configuredshaft rotatably jointed to a fan base, said shaft being extendedradially to form a plurality of fan leaves, said fan base being a squarehollow casing having at least an opening penetrating the casing itselfin its top end and lateral wall, and an electrical device for drivingsaid fan body, in which: a recess for positioning a shaft end is formedat respective corresponding positions of the lower surface of a top endand the upper surface of a bottom end in said fan base; the electricaldevice is extended to the upper surface of the bottom end of the fanbase to form a plurality of electromagnets, which is aligned surroundingsaid recess in the upper surface of the bottom end of said fan base;said shaft having a plurality of permanent magnets in its bottom face istapered at both ends for mating with the recesses of said fan base sothat each shaft end can be rotatably fitted in each recess; and amagnetic N-zone, an S-zone, and a Neutral zone are arranged repeatedlyand rotationally in every permanent magnet, and the magnetic zones ofeach electromagnet are controlled correspondingly to that of each saidpermanent magnet.
 2. The shaftless cooling fan according to claim 1, inwhich each shaft end is substantially point-contacted with each recess.